Gas turbine engines may comprise a compressor for pressurizing an air supply, a combustor for burning a fuel, and a turbine for converting the energy from combustion into mechanical energy. The combustor may have an inner liner and an outer liner that define a combustion chamber. A fuel injector would typically introduce fuel into the front section of the combustor. As the fuel burns, nitrogen oxide (NOx) and other emissions may be produced. Such emissions are subject to administrative regulation. To reduce NOx emission and improve pattern factor, a fuel staged lean burn combustor may be used. For example, axially staged combustors may include pilot fuel injectors and radial main mixers. The pilot fuel injectors introduce fuel into the front section of the combustor, while the radial main mixers located downstream of the pilot injectors deliver fuel/air mixture radially at an angle into the combustor.
When injected normally into the combustor, the main flame generated by the main radial mixer may have a very long flame length. As a result, the main flame may either extend to the combustor exit or be quenched by the opposite side liner. As shorter combustor lengths typically provide better performance, long flame lengths corresponding to greater combustor lengths may decrease performance. Similarly, quenching the main flame on the opposite side liner may result in a poor burn. Poor mixing will result in poor pattern factor.